Atom optics relies on the concept of providing beams of atoms sufficiently slowed down for their de Broglie wavelengths to be of manageable nanometer-scale dimensions. An ongoing challenge is to develop suitable optics devices that will allow beams of atoms, or of ions or molecules or charged particles, to be usefully employed for their wave-like properties.
For example, interposition of an atomic lens can allow a beam of atoms from a diffuse source to be focused into an array of lines and dots of nanometer dimensions, a technique that can be applied as a novel form of nanofabrication. Such developments were described by R. J. Celotta, R. Gupta, R. E. Scholten and J. J. McClelland, in “Nanostructure fabrication via laser focused atomic deposition”, J. Appl. Phys. 79 (80, 15 Apr. 1996a; J. J. McClelland and R. J Celotta, in “Laser-Focused Atomic Deposition—Nanofabrication via Atom Optics”, pre-print, NIST; J. J. McClelland, “Nanofabrication via Atom Optics” in Handbook of Nanostructured Materials and Nanotechnology, Vol. 1, 335-385 (2000); M. R. Walkiewicz, “Manipulation of Atoms Using Laser Light”, PhD Thesis, University of Melbourne, (2000) 222 p.' J. J, McClelland, William R. Anderson, Curtis C. Bradley, Mirek Walkiewicz, Robert J. Celotta, Erich Jurdik and Richard D. Deslattes, “Accuracy of nanoscale pitch standards fabricated by laser-focused atomic deposition” NIST Journal of Research 108(2), 99-113 (2003) Feb. 14, 2003. The NIST researchers used a laser light tuned near an atomic transition to form an array of atom lenses for focusing a beam of atoms into an array of dots of a size as small as 30 nanometers.
It is an object of this invention to provide a device useful in the field of electromagnetic waveguides and particle optics, and consequently in the manipulation of particle beams in the field of nanofabrication.
The invention borrows a structure known in another branch of nanotechnology and modifies and extends it for the purposes of the present invention. The known structure is the micro or nano electrical conductor crossbar network, previously described in a range of contexts including a displacement or vibration-measuring system (international patent publication WO 00/14476), a memory system (U.S. Pat. No. 6,128,214) and a demultiplexer (U.S. Pat. No. 6,256,767).
A micro or nano electrical conductor crossbar network comprises a set of two separate substrates, each having a two dimensional array of micro- or nano-wires (conductors) deposited on it and extending as an array of parallel lines on the substrates. The two substrates are separated by suitable distance. The arrays of parallel micro- or nano-conductors on the two substrates facing each other may be at an arbitrary angle with respect to each other, but of particular interest for some applications is the case where the arrays are at a right angle. Thus a crossbar network consists of a two dimensional array of micro or nanometer scale devices, each comprising a cross-over point or a junction formed where a pair of spaced conductors cross but do not touch one another. Each junction has a state, e.g. capacitance, or quantum tunnelling current conductance, that can be altered by applying a voltage across the respective conductors that cross at the junction.
The most significant feature of the aforementioned U.S. patents is the presence of a connector species forming an electron donor-bridge-acceptor (DBA) molecular junction (a molecular switch) at each cross-over, while international patent publication WO 00/14476 does not include a specific connector species, not even calls for them, but instead relies on a sensitivity to quantum tunnelling current at the cross-over points, and discloses how the set of cross-over points will form an artificial scattering lattice effective to scatter electromagnetic wave or a beam of atoms directed parallel to the sandwich structure into the space between the conductor layers. Each conductor may be independently connected electrically, i.e. they have no common bias; there will then be a pixelised array which is an analogue of a two-dimensional “pinball game” for waves or atoms, with predefined scattering centres. This concept is further developed in the present application and broadened to include larger dimensions.
Reference to the aforementioned patent publication and patents is not to be construed as an admission that their content, whether in whole or in part, is or has been common general knowledge.